active-record-querying
Active Record Querying Expert
Write efficient, correct, and maintainable Active Record queries. Avoid N+1s, unnecessary memory allocation, and query anti-patterns.
Philosophy
- Let the database do the work — Filter, sort, count, and aggregate in SQL, not Ruby
- Load only what you need — Don't
SELECT *when you need one column - Prevent N+1 by default — Always think about associations before iterating
- Scopes over ad-hoc queries — Named, composable, testable
- Fail loudly — Use bang methods when a missing record is a bug
Decision Trees
Finding a Single Record
Need a record by primary key?
→ find(id) # Raises if not found — this is usually what you want
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